In the fitting up and laying of large-diameter pipe, where apertured pipe flanges are welded to respective lengths of pipe, and then adjacent pipe flanges are bolted together, the correct angular alignment of the pipe flanges is essential or they cannot be joined by bolts. This represents no particular problem when two straight unbent lengths of pipe are to be joined, because the entire length of one pipe can be rotated so the apertures in the pipe flanges line up, and then the flange at the other end can be welded on, and the process repeated. It is not so simple, however, when one of the pipes has a joint in it that forms an angle, or when both of them do.
It is extremely inconvenient to weld a pipe flange onto a pipe with the pipe already installed in its ultimate installed position. It is better practice to lay the jointed pipe flat on the floor, and do the job in a shop. Or, if the job is done in the field, it is better practice to perform the task at ground level. However, there is a more complicated angular relationship, when the pipe is bent than when it is straight, because when the jointed pipe is erected, the pipe flange will have rotated. Accordingly, when a pipe flange is attached to a length of bent pipe, allowance must be made for the change in spatial alignment which will result when the pipe is erected in its ultimate position.
An object of this invention is to provide a tool for angularly aligning a pipe flange relative to a pipe which is easy to use, and accurate in its results.